ScienceNasa.gov - 24 November 2013
The Heliospheric Imager on NASA's STEREO-A spacecraft is tracking Comet ISON as it plunges toward the sun. In this movie, which spans a two day period from Nov. 20 to Nov. 22, 2013, the sun is off-screen to the right. Coincidentally, Comet Encke is present too
Nov. 24, 2013: In 2007, astronomers were amazed when a solar storm hit Comet Encke. NASA STEREO spacecraft watched as a CME (coronal mass ejection) struck the comet head on and ripped off its tail.
The same thing could be in store for Comet ISON--only worse.
On Nov. 28th, Comet ISON will pass through the sun's atmosphere, flying little more than a million kilometers above the sun's surface. It will be ~30 times closer to the sun than Encke was in 2007 and more likely to encounter a ferocious solar storm.
"For one thing," says Angelos Vourlidas of the Naval Research Lab and a participant in NASA's Comet ISON Observing Campaign (CIOC), "the year 2007 was near solar minimum. Solar activity was low. Now, however, we are near the peak of the solar cycle and eruptions are more frequent."
